Drafting machine



Aug. 26; 1969 A. A. GOERZ DRAF'IING MACHINE Filed May 6, 1968 I N VE N TOR.

mrraeA/a x United States Patent 3,462,846 DRAFTING MACHINE Arthur A. Goerz, 2708 W. 75th St, Los Angeles, Calif. 90043 Filed May 6, 1968, Ser. No. 726,862 Int. Cl. B431 13/02 US. Cl. 33-109 7 Claims ABSTRACT OF THE DISCLOSURE A drafting machine which includes a horizontally slidable member having a side edge which forms a guiding surface, an opening through the member spaced away from the guiding surface, a cylindrical guide roller having a high-friction surface located above the opening with its axis of rotation horizontally disposed, and a spring support normally maintaining the guide roller in its elevated position but depressible to permit the guide roller to pass partially through the opening for engaging a sheet of drafting paper upon which the member is supported, while still maintaining contact between the member and the paper.

Background of the invention In mechanical drafting work it is well known to utilize a T-square, or similar apparatus, for the purpose of locating and marking spaced parallel lines. Such apparatus is bulky and unwieldy, and it will be desirable to provide more compact apparatus to serve the same purposes. A drafting machine of that general type was disclosed in my Patent 2,595,842 issued May 6, 1952.

According to the present invention there is provided an improved drafting machine, characterized by superior performance, as well as being simpler in construction and cheaper to manufacture than any previous machine.

Thus the primary purpose of the present invention is to provide a small, compact drafting machine adapted for locating and marking parallel lines, which may be quickly and easily moved by the draftsman from one location to another, Without any loss of alignment.

Drawings summarized FIGURE 1 is a top plan View of a presently preferred embodiment of the invention;

FIGURE 2 is an elevational view of the drafting machine of FIGURE 1, resting upon a sheet of drafting paper, and having all the guide rollers thereof supported in their normal elevated positions;

FIGURE 3 is an exploded perspective view of the guide roller and spring assembly of the device;

FIGURE 4 is a perspective view of the handle; and

FIGURE 5 is a fragmentary cross-sectional view of the rotatable suspension for the guide rollers.

Preferred embodiment Referring now to the drawing, a triangle is formed of a rigid, transparent plastic sheet, whose undersurface is adapted to slide in any horizontal direction as desired upon the surface of a sheet of drafting paper 15. The triangle 10 has an apex 11 that is formed by the intersection of elongated side edges 12, 13, which form mutually perpendicular linear guiding surfaces. A pair of openings 16a, 16b are formed in the member 10 at equal distances from the guiding surface 12; and openings 17a, 17b are also formed in the member 10 at equal distances from the guiding surface 13.

A guide roller assembly 20 identical with is normally supported above the openings 16a, 16b, with its axis of rotation aligned parallel to the guiding surface 12. The guide roller assembly 20 includes a pair of cylindrical 3,462,846 Patented Aug. 26, 1969 guide rollers 21, 22, which are fixedly interconnected on an axle 23, so as to rotate in synchronism about a common axis of revolution. Each of the rollers 21, 22 has a high-friction cylindrical surface 27, which is adapted to frictionally engage the surface of the drafting paper 15.

A spring suspension assembly 40 includes a sheet member 41, preferably spring steel, which has considerable width, but simulates a arc. The longitudinal central portion 42 of the sheet member 41 is substantially fiat, but the end portions 43 and 44 are bent upwardly. A hearing 45 is attached to edge 43 of the sheet member 41, and a bearing 46 is attached to the edge 44, the bearings 45 and 46 being so alignable that their longitudinal axes are mutually perpendicular. The axle 23 is rotatably supported within bearing 45.

Guide roller assembly 30 identical with 20 is normally supported in an elevated position above the openings 17a, 17b. Assembly 30 includes a pair of guide rollers 31, 32, which are rigidly interconnected by an axle 33 so as to rotate in synchronism on a common axis. Each of the rollers 31, 32 has a high-friction cylindrical surface 27, adapted for frictionally engaging the surface of drafting paper 15. Axle 33 is rotatably supported within bearing 46.

A handle 50 is positioned on the upper surface of sheet member 41, above the longitudinal central portion 42 thereof. A pair of fastening screws 51 extend from the undersurface of the triangle member 10, through corresponding openings in sheet member 41, and the handle 50, so as to secure the triangle 10, sheet member 41, and handle 50 together.

Triangle 10 also includes a protractor 14, whose center of rotation is the apex 11a. Protractor 14 includes degree markings from 0 to 45 from each respective base line parallel to an edge of triangle 10.

In operation, either of the guide roller assemblies 20,

30 may be selectively depressed for engaging the surface of the drafting paper 15, through the corresponding pair of openings 16a, 1611 or 17a, 17b. When the guide roller assembly is thus depressed, its axis of rotation continues to remain parallel to the associated linear guiding surface 12 and 13. The reason this parallel relationship is rigidly maintained is the substantial width of the sheet member 41 adjacent its ends 43, 44. Thus when the guide roller assembly 20 is selectively depressed, the triangle member 10 is concurrently pressed against the paper with greater than normal force, but nevertheless the triangle member 10 may be moved so that the linear guiding surface 12 assumes a position precisely parallel to its previous position. In like manner, when guide roller assembly 30 is selectively depressed, triangle member 10 assumes a position in which linear guiding surface 13 is precisely parallel to its prior position.

It will therefore be seen that the drafting machine of the present invention can be freely moved to any location on the surface of the drafting paper 15, without requiring the use of a T-square or other extraneous anchorages. Furthermore, the nature of the present machine is such that the draftsman may work up to the very edges and corners of the drafting paper, irrespective of the prsence or absence of a flat supporting surface beyond those edges, and still draw mutually perpendicular parallel lines.

The operation of the machine is not restricted to locating lines that are parallel to the original locations of the linear guiding surfaces '12, 13. The protractor 14 may be utilized for locating a new line at any desired angle to one of the original guide lines. Such a new guide line then provides the basis for a whole new family of other lines parallel to it.

In each guide roller assembly the cylindrical guide rollers such as 21, 22 may, for example, be made of solid metal, with the cylindrical surfaces 27 being knurled. The

interconnecting axle such as 23 is rigidly connected to the two cylindrical rollers in any desired manner.

It is significant that the radius of each of the guide rollers 21, 22, 31, 32 is at least several times the thick ness of the triangle member (see FIGURE 2). Due to this large radius value, when one of the guide roller assemblies is depressed, the associated pair of guide rollers engage the surface of the drafting paper not at a single point, but throughout a substantial area, resulting from the fact that a significant portion of the total circumference of the guide roller achieves a bearing contact with the drafting paper. It is this substantial area of contact, together with the high-friction surface of the guide rollers, which insures the maintaining of alignment of the drafting machine as it is being moved from one location to another, so that the drafting machine does not change its angular position relative to the paper.

Alternate forms Although the presently illustrated form of the drafting machine is a triangle, having two linear guiding surfaces 12, 13, it will be readily appreciated that the invention may equally well be incorporated into a drafting machine having a single linear guiding surface.

In the presently illustrated embodiment of the invention each linear guiding surface is accompanied by a pair of openings, such as 17a, 17b, through which a pair of associated cylindrical guide rollers are selectively depressed. However, for certain purposes it may be preferred to employ a single opening and a single guide roller. If a single guide roller is used, its length does not necessarily have to be equal to the separation distance between the two guide rollers of a pair, as used in the present embodiment. It may be either shorter or longer as preferred. The use of a guide roller pair does, however, provide some advantage, because for the same amount of guiding action achieved the weight and hence cost of the rollers is reduced.

While metal guide rollers have been illustrated herein, it is also possible to use plastic rollers made of a tacky plastic matrial, which also has a high degree of surface friction for engaging the surface of the drafting paper 15.

The invention has been described in considerable detail in order to comply with the patent laws by providing a full public disclosure of at least one of its forms. However, such detailed description is not intended in any way to limit the broad features or principles of the invention, or the scope of patent monopoly to be granted.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A drafting machine comprising:

a drafting member adapted to slide on a sheet of drafting paper to guide the marking of lines thereon, said member having an opening therethrough;

a guide roller having a cylindrical surface adapted for frictionally engaging the paper, being normally disposed above said member and out of engagement with the paper;

and spring mounting means carried by said member and supporting said guide roller over said opening on a generally horizontal axis of rotation, said spring mounting means including a resilient metallic sheet having one portion secured to the upper surface of said drafting member and another portion from which said guide roller is rotatably suspended;

said guide roller being depressible against the force of said spring mounting means so as to engage the paper through said opening to thereby guide the movement of said member across the paper while maintaining the angular position of said member relative to the paper, said member being concurrently pressed with greater than normal force against the paper.

2. A drafting machine as claimed in claim 1 which includes a fixed axle concentrically attached to said guide roller, and wherein said spring mounting means include a housing within which said axle is rotatably supported, said other portion of said resilient metallic sheet being secured to said housing.

3. A drafting machine comprising:

a drafting member adapted to slide on a sheet of drafting paper to guide the marking of lines thereon, said member having a pair of openings therethrough;

a pair of guide rollers each having a cylindrical surface adapted for frictionally engaging the paper, and being normally disposed above said member and out of engagement with the paper;

a fixed axle concentrically attached to both of said guide rollers so that said guide rollers turn together on a common axis of rotation;

and spring mounting means carried by said member and supporting said guide rollers over said openings on a generally horizontal axis of rotation, said spring mounting means including a housing within which said axle is rotatably supported, said housing being disposed between said rollers;

said guide rollers being depressible against the force of said spring mounting means so as to engage the paper through said openings to thereby guide the movement of said member across the paper while maintaining the angular position of said member relative to the paper, said member being concurrently pressed with greater than normal force against the paper.

4. A drafting machine as claimed in claim 3 wherein said housing is located precisely at the midpoint between said two guide rollers, whereby said housing may be manually depressed in such manner as to distribute the downward pressure applied on the drafting paper equally between said two guide rollers.

5. A drafting machine as claimed in claim 3 which includes two pairs of said cylindrical guide rollers, said spring means including a metallic sheet which has considerable width but is curved throughout its length to assume substantially a ninety degree are, the longitudinal center of said metallic sheet being secured to the upper surface of said drafting member and the ends of said metallic sheet being curved upwards, the housings for respective pairs of guide rollers being attached to respective ends of said metallic sheet.

6. A drafting machine as claimed in claim 5 which further includes a handle secured above the longitudinal central portion of said metallic sheet.

7. A drafting machine as claimed in claim 3 wherein said spring mounting means includes a resilient metallic sheet having one portion secured to the upper surface of said drafting member and another portion secured to said housing.

References Cited UNITED STATES PATENTS D. 136,091 8/1943 Tripp 33109 X 652,832 7/1900 Carmical 33-109'X 1,064,222 6/1913 Holmes 33109 X 2,506,243 5/1950 Sill 33-400 FOREIGN PATENTS 1,086,675 8/1954 France.

3,110 1897 Great Britain.

HARRY N. HAROIAN, Primary Examiner 

